I don't know if you'll remember this. This was years ago, back when you were in New England for the summer, clearing out your dad's place after he died. We were talking one night over skype - I was in Madison, if I remember right - you were on your childhood bed, in your childhood room, propped up by dusty stuffed toys, and taking these long, meditative draws from your dad's old pipe. During these lulls in conversation, whisps of pixelated, low-bitrate jazz would waft in from the kitchen, where his records were kept in permanent rotation. You told me that for a while now, whenever the sun went down, you had taken to keeping the place as dark and familiar and welcoming as you could. Drifting from room to room by candlelight. Peering through the hallway mirror into the shadows over your reflection's shoulder. Hoping to be haunted.

I never believed in ghosts.

I mean, that said, whenever the train passes your flat - even today - I still look up to see if you're there. Perched muppetlike at the upperfloor window, waving wildly down at a train full of strangers because you know I'm in among them somewhere. Even though you haven't been there for six years. I'm reminded of something I overheard once at a Philosophy department function back in 2008, it must have been. Two professors discussing a theory I have never been able to place: that our memories, and our thoughts, and our emotions can be argued to inhabit physical space. That we shed them in our wake like footprints in fresh concrete, and they stay precisely where we leave them, waiting for us to pass this way again some day. Retrace them. Resurrect them, in a way.

I might be wrong, but I think that's what's happening here. That bittersweet image of you at the upperfloor window - smiling, waving - is effectively the first stop on this train's route. The tracks pass directly through this memory, these thoughts, these emotions, on the way to Ardrossan Harbour from Glasgow Central Station to catch the six o'clock ferry.

Today especially it is a welcome distraction.

Because I'm going home for Christmas. For the first since my Dad died. And that big old converted hotel by the sea that I grew up in - that I spent 31 consecutive christmases in without fail, sometimes with my grandparents, sometimes my aunt and uncle, once with you, but always at the very least my mum, my dad and I - that house is going to have just two people in it for Christmas for the first time since I have been alive. Two people tracking mud through the hallways. Trundling along as if on rails, with no choice but to retrace footprints in the carpet from a long time ago. Some decades old. And in doing so, pass through memory after thought after cold, grey emotion, like a hundred thousand unwelcome guests crammed into the narrow corridors of our dark hotel by the sea.

As I said, I don't believe in ghosts, but that doesn't matter really. I don't think you did either. I think I'm about to find out what it actually feels like to be haunted.